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[217.105.46.58]) by smtp.gmail.com with ESMTPSA id qk29-20020a170906d9dd00b0098e34446464sm4327706ejb.25.2023.07.30.01.27.21 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 30 Jul 2023 01:27:21 -0700 (PDT) From: Nam Cao To: Paul Walmsley , Palmer Dabbelt , Albert Ou , linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org Cc: Nam Cao Subject: [PATCH 2/3] riscv: kprobes: simulate c.jr and c.jalr instructions Date: Sun, 30 Jul 2023 10:27:08 +0200 Message-Id: X-Mailer: git-send-email 2.34.1 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" kprobes currently rejects c.jr and c.jalr instructions. Implement them. Signed-off-by: Nam Cao Reviewed-by: Charlie Jenkins --- arch/riscv/kernel/probes/decode-insn.c | 4 +-- arch/riscv/kernel/probes/simulate-insn.c | 37 ++++++++++++++++++++++++ arch/riscv/kernel/probes/simulate-insn.h | 2 ++ 3 files changed, 41 insertions(+), 2 deletions(-) diff --git a/arch/riscv/kernel/probes/decode-insn.c b/arch/riscv/kernel/pro= bes/decode-insn.c index 39adb07a342d..6dba23a55ac7 100644 --- a/arch/riscv/kernel/probes/decode-insn.c +++ b/arch/riscv/kernel/probes/decode-insn.c @@ -29,14 +29,14 @@ riscv_probe_decode_insn(probe_opcode_t *addr, struct ar= ch_probe_insn *api) * TODO: the REJECTED ones below need to be implemented */ #ifdef CONFIG_RISCV_ISA_C - RISCV_INSN_REJECTED(c_jr, insn); RISCV_INSN_REJECTED(c_jal, insn); - RISCV_INSN_REJECTED(c_jalr, insn); RISCV_INSN_REJECTED(c_beqz, insn); RISCV_INSN_REJECTED(c_bnez, insn); RISCV_INSN_REJECTED(c_ebreak, insn); =20 RISCV_INSN_SET_SIMULATE(c_j, insn); + RISCV_INSN_SET_SIMULATE(c_jr, insn); + RISCV_INSN_SET_SIMULATE(c_jalr, insn); #endif =20 RISCV_INSN_SET_SIMULATE(jal, insn); diff --git a/arch/riscv/kernel/probes/simulate-insn.c b/arch/riscv/kernel/p= robes/simulate-insn.c index 3ba45c612cd8..1ead6f4951f9 100644 --- a/arch/riscv/kernel/probes/simulate-insn.c +++ b/arch/riscv/kernel/probes/simulate-insn.c @@ -212,3 +212,40 @@ bool __kprobes simulate_c_j(u32 opcode, unsigned long = addr, struct pt_regs *regs =20 return true; } + +static bool __kprobes simulate_c_jr_jalr(u32 opcode, unsigned long addr, s= truct pt_regs *regs, + bool is_jalr) +{ + /* + * 15 12 11 7 6 2 1 0 + * | funct4 | rs1 | rs2 | op | + * 4 5 5 2 + */ + + unsigned long jump_addr; + + u32 rs1 =3D (opcode >> 7) & 0x1f; + + if (rs1 =3D=3D 0) /* C.JR is only valid when rs1 !=3D x0 */ + return false; + + if (!rv_insn_reg_get_val(regs, rs1, &jump_addr)) + return false; + + if (is_jalr && !rv_insn_reg_set_val(regs, 1, addr + 2)) + return false; + + instruction_pointer_set(regs, jump_addr); + + return true; +} + +bool __kprobes simulate_c_jr(u32 opcode, unsigned long addr, struct pt_reg= s *regs) +{ + return simulate_c_jr_jalr(opcode, addr, regs, false); +} + +bool __kprobes simulate_c_jalr(u32 opcode, unsigned long addr, struct pt_r= egs *regs) +{ + return simulate_c_jr_jalr(opcode, addr, regs, true); +} diff --git a/arch/riscv/kernel/probes/simulate-insn.h b/arch/riscv/kernel/p= robes/simulate-insn.h index 4bd6c266e7d3..472a1948ec4f 100644 --- a/arch/riscv/kernel/probes/simulate-insn.h +++ b/arch/riscv/kernel/probes/simulate-insn.h @@ -25,5 +25,7 @@ bool simulate_branch(u32 opcode, unsigned long addr, stru= ct pt_regs *regs); bool simulate_jal(u32 opcode, unsigned long addr, struct pt_regs *regs); bool simulate_jalr(u32 opcode, unsigned long addr, struct pt_regs *regs); bool simulate_c_j(u32 opcode, unsigned long addr, struct pt_regs *regs); +bool simulate_c_jr(u32 opcode, unsigned long addr, struct pt_regs *regs); +bool simulate_c_jalr(u32 opcode, unsigned long addr, struct pt_regs *regs); =20 #endif /* _RISCV_KERNEL_PROBES_SIMULATE_INSN_H */ --=20 2.34.1